1-201359245-G-C

Variant names:

• chr1-201359245-G-C
• rs121964857
• NM_001276345.2:c.862C>G

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 6P and 2B. PM1 PM2 PM5 BP4_Moderate

The NM_001276345.2(TNNT2):​c.862C>G​(p.Arg288Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R288P) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TNNT2 NM_001276345.2 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.770
• Publications: 0 publications found

Genes affected

TNNT2 (HGNC:11949): (troponin T2, cardiac type) This gene encodes the cardiac isoform of troponin T. The encoded protein is the tropomyosin-binding subunit of the troponin complex, which is located on the thin filament of striated muscles and regulates muscle contraction in response to alterations in intracellular calcium ion concentration. Mutations in this gene have been associated with familial hypertrophic cardiomyopathy as well as with dilated cardiomyopathy. [provided by RefSeq, May 2022]

TNNT2 Gene-Disease associations (from GenCC):

• dilated cardiomyopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• dilated cardiomyopathy 1D

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics
• hypertrophic cardiomyopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• hypertrophic cardiomyopathy 2

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae)
• hypertrophic cardiomyopathy 3

  Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
• cardiomyopathy, familial restrictive, 3

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• familial isolated dilated cardiomyopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• familial isolated restrictive cardiomyopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• left ventricular noncompaction

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• cardiomyopathy

  Inheritance: AR Classification: LIMITED Submitted by: Ambry Genetics
• arrhythmogenic right ventricular cardiomyopathy

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ENSG00000286600 (HGNC:):

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 21 uncertain in NM_001276345.2
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr1-201359244-C-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 177635.
• BP4: Computational evidence support a benign effect (MetaRNN=0.24035618).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001276345.2. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TNNT2	NM_001276345.2	MANE Select	c.862C>G	p.Arg288Gly	missense	Exon 17 of 17	NP_001263274.1
	TNNT2	NM_000364.4		c.853C>G	p.Arg285Gly	missense	Exon 16 of 16	NP_000355.2
	TNNT2	NM_001406723.1		c.853C>G	p.Arg285Gly	missense	Exon 16 of 16	NP_001393652.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TNNT2	ENST00000656932.1	MANE Select	c.862C>G	p.Arg288Gly	missense	Exon 17 of 17	ENSP00000499593.1
	TNNT2	ENST00000367322.6	TSL:1	c.820C>G	p.Arg274Gly	missense	Exon 15 of 15	ENSP00000356291.2
	TNNT2	ENST00000367320.6	TSL:1	c.733C>G	p.Arg245Gly	missense	Exon 15 of 15	ENSP00000356289.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.70
CardioboostCm	Uncertain	0.30
BayesDel_addAF	Uncertain	0.044	T
BayesDel_noAF	Benign	-0.18
CADD	Uncertain	23
DANN	Uncertain	0.98
DEOGEN2	Uncertain	0.56	D
Eigen	Benign	-0.12
Eigen_PC	Benign	-0.063
FATHMM_MKL	Benign	0.71	D
LIST_S2	Uncertain	0.89	D
M_CAP	Pathogenic	0.30	D
MetaRNN	Benign	0.24	T
MetaSVM	Benign	-0.51	T
MutationAssessor	Benign	0.69	N
PhyloP100		0.77
PrimateAI	Uncertain	0.57	T
PROVEAN	Benign	-1.1	N
REVEL	Uncertain	0.41
Sift	Benign	0.33	T
Sift4G	Benign	0.24	T
Polyphen		0.36	B
Vest4		0.29
MutPred		0.33		Loss of methylation at R288 (P = 0.0188)
MVP		0.88
MPC		1.6
ClinPred		0.82	D
GERP RS		3.0
Varity_R		0.16
gMVP		0.53
Mutation Taster		=15/85	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs121964857; hg19: chr1-201328373;